Method for testing gas turbine engines

ABSTRACT

A method for testing a cooling system for use in a gas turbine engine control system is provided. The method includes connecting an inlet of the cooling system to a differential pressure sensor, connecting an outlet of the cooling system to the differential pressure sensor, and determining whether or not a difference in pressure exists between the inlet and outlet, wherein such a pressure difference is indicative of whether cooling fluid is flowing through the cooling system.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT

This invention was made with Government support under contract numberN00019-96-C-0176. The Government may have certain rights in thisinvention.

BACKGROUND OF THE INVENTION

This invention relates generally to gas turbine engines, and morespecifically, to a method and apparatus for monitoring cooling flow toelectronic controls.

At least some known gas turbine engines include cooling systems thatutilize fuel flows to facilitate cooling components within the gasturbine engine. For example, known cooling systems are used to regulatethe temperature of a full authority digital engine control (FADEC)system used with the gas turbine engine. To facilitate maintenance,often no-leak quick-disconnect fittings are used to connect adjacentcooling lines in the cooling system. Moreover, such fittings alsofacilitate assembly of the engine to the aircraft.

At least some known gas turbine engines include electronic componentsthat are cooled using fuel. Specifically, fuel is channeled from asupply to each electronic component wherein it is routed through amechanism to facilitate cooling the electronic components. Spent coolingfuel is then returned to the fuel supply. If an electronic component isnot properly cooled, the electronic component could overheat and theelectronic component could fail.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, a method for testing a cooling system for use in a gasturbine engine control system is provided. The method includesconnecting an inlet of the cooling system to a differential pressuresensor, connecting an outlet of the cooling system to the differentialpressure sensor, and determining whether or not a difference in pressureexists between the inlet and outlet, wherein such a pressure differenceis indicative of whether cooling fluid is flowing through the coolingsystem.

In a further aspect, a cooling system for a gas turbine engine controlsystem is provided. The cooling system includes an inlet portion coupledin fluid communication with a source of cooling fluid. The inlet portionis configured to channel cooling fluid from the cooling fluid source tothe control system to facilitate cooling the control system. The coolingsystem also includes an outlet portion configured to channel coolingfluid from the control system to one of the cooling fluid source and areservoir. The cooling system further includes a differential pressuresensor in flow communication with the inlet portion and the outletportion. The differential pressure sensor is configured to sense whethera pressure difference exists within the inlet and outlet portions.

In a further aspect, a gas turbine engine is provided. The gas turbineengine includes a compressor, a combustor in flow communication withsaid compressor, a turbine in flow communication with said combustor, acontrol system, and a cooling system. The cooling system includes aninlet portion coupled in fluid communication with a source of coolingfluid. The inlet portion is configured to channel cooling fluid from thecooling fluid source to the control system to facilitate cooling thecontrol system. The cooling system further includes an outlet portionconfigured to channel cooling fluid from the control system to one ofthe cooling fluid source and a reservoir. The cooling system alsoincludes a differential pressure sensor in flow communication with theinlet portion and the outlet portion. The differential pressure sensoris configured to sense whether there is a difference in pressure betweencooling fluid within the inlet and outlet portions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an exemplary gas turbine engine;

FIG. 2 is a schematic illustration of an exemplary control system andassociated cooling system for use with a gas turbine engine, for examplethe engine shown in FIG. 1;

FIG. 3 is a schematic illustration of a cooling plate for use with thecooling system shown in FIG. 2; and

FIG. 4 is a logic diagram illustrating an exemplary method for testing acooling system, for example the cooling system shown in FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic illustration of an exemplary gas turbine engine 10including a low pressure compressor 12, a high pressure compressor 14,and a combustor 16. Engine 10 also includes a high pressure turbine 18and a low pressure turbine 20. Compressor 12 and turbine 20 are coupledby a first shaft 21, and compressor 14 and turbine 18 are coupled by asecond shaft 22. Gas turbine engine 10 may include one or moreelectronic controls.

In operation, air flows through low pressure compressor 12 and a portionof that compressed air is channeled to high pressure compressor 14. Thehighly compressed air is channeled to combustor 16, where it is mixedwith fuel and ignited to produce a combustion gas flow that drivesturbines 18 and 20.

FIG. 2 is a schematic illustration of an exemplary electronic controlsystem 99 for use with a gas turbine engine, for example engine 10(shown in FIG. 1), and an exemplary cooling system 100 for use withcontrol system 99. FIG. 3 is a schematic illustration of a cooling plate130 that may be used with cooling system 100. A cooling plate 130 is amechanism used to facilitate cooling of electronic components ofelectronic control system 99. Cooling plate 130 is typically adjacent toan electronic component, and includes a passage, channels, or any othersuitable means to enable fuel to flow through cooling plate 130. As fuelflows through the passage or channels, the electronic component iscooled.

In the exemplary embodiment, control system 99 includes a plurality ofcontrol subsystems 110 for use in controlling engine 10. Although fivecontrol subsystems 110 are illustrated, control system 99 may includeany number of control subsystems 110 for controlling any number offunctions of engine 10 and/or related to engine 10. Moreover, controlsystem 99 may include any suitable type of control subsystem(s) 110 eachfor use in controlling any function(s) related to engine 10. As shown inFIG. 2, cooling system 100 also includes a pressure sensor 112. Sensor112 senses, at least in part, whether there is cooling fluid pressurewithin cooling system 100 indicating whether cooling fluid is capable offlowing from a fuel source. Sensor 112 may be any suitable device and/ormeans used to sense operational pressure. Sensor 112 is positionableanywhere within cooling system 100 that enables sensor 112 to measurewhether there the capability of cooling fluid to flow from a fuelsource. Alternatively, sensor 112 is positioned within the aircraftprior to the quick-disconnect fittings. Alternatively, cooling system100 does not include sensor 112. The ability to confirm cooling flow inany one of the control subsystems 110 assures that quick-disconnectfittings at the supply and return are connected, so that cooling fluidwill flow to provide cooling when the engine is running.

In the exemplary embodiment, control system 99 includes a prognosticsand health area manager (PHAM) control subsystem 120 for systemmonitoring, a plurality of full authority digital engine control (FADEC)control subsystems 122 and 124 for engine and power plant control, anignition control subsystem 126 for ignition control and monitoring, andan anti-ice control subsystem 128 for control of engine inletanti-icing. FADEC control subsystems 122 and 124 include thermal inertiasuch that FADEC control subsystems 122 and 124 include the ability of toconduct and store heat. Control system 99 may be coupled at any suitablelocation on, within, and/or adjacent engine 10. Alternatively, controlsystem 99 may be located away from engine 10.

Cooling system 100 includes a conduit system 114 that is coupled to asource (not shown) of cooling fluid. Any suitable cooling fluid thatenables cooling system 100 to function as described herein may beutilized in cooling system 100. For example, in the exemplaryembodiment, the cooling fluid is a fuel, such as, but not limited to,fuel used to operate engine 10. Moreover, the cooling fluid may be anysuitable source at any suitable location, whether onboard or remote fromengine 10. For example, in the exemplary embodiment, the source ofcooling fluid is a fuel tank (not shown) that supplies fuel to engine 10for producing the combustion gas flow.

Cooling fluid is channeled from the cooling fluid source into conduitsystem 114 wherein the fluid is channeled to and/or adjacent to eachcontrol subsystem 110 to facilitate cooling thereof. In the exemplaryembodiment, control subsystems 110 are positioned relative to conduitsystem 114 in a parallel flow relationship with respect to one anotherfor receiving cooling fluid. In the exemplary embodiment, controlsubsystems 110 are positioned in parallel such that if one controlsubsystem 110 is receiving cooling fluid, each control subsystem 110 isreceiving cooling fluid. In an alternative embodiment, controlsubsystems 110 may be positioned relative to conduit system 114 in aseries flow relationship with respect to one another for receivingcooling fluid. In other embodiments, at least some of control subsystems110 are in a series flow relationship while at least some others are ina parallel flow relationship.

In the exemplary embodiment, conduit system 114 includes an inletportion 117 and an outlet portion 119. Inlet portion 117 extends to eachof the plurality of control subsystems 110 to channel cooling fluid fromthe cooling fluid source to, and/or adjacent to, each control subsystem110. Outlet portion 119 channels cooling fluid from, and/or adjacentfrom, each of control subsystems 110 to the cooling fluid source and/orto a reservoir (not shown). For example, in the exemplary embodiment,the cooling fluid is channeled through conduit system 114 from inletportion 117 to an inlet portion 129, 132, 134, 136, and 138 associatedwith each of PHAM 120, FADEC 122, FADEC 124, ignition control subsystem126, and anti-ice control subsystem 128, respectively, and from anoutlet portion 140, 142, 144, 146, and 148 associated with each of PHAM120, FADEC 122, FADEC 124, ignition control subsystem 126, and anti-icecontrol subsystem 128, respectively, to the cooling fluid source and/orthe reservoir.

The cooling fluid may cool each control subsystem 110 using any suitableprocess, structure, and/or means. As such, and as described above, inletportions 129, 132, 134, 136, and 138 may channel cooling fluid directlyto one or more of respective subsystems 120, 122, 124, 126, and/or 128,or alternatively may channel cooling fluid adjacent to one or more ofrespective subsystems 120, 122, 124, 126, and/or 128. For example, inthe exemplary embodiment, each subsystem 120, 122, 124, 126, and 128includes a cooling plate 130 coupled thereto. Inlet portions 129, 132,134, 136, and 138 and outlet portions 140, 142, 144, 146, and 148 arecoupled in flow communication to each control subsystem cooling plate130 for channeling cooling fluid thereto. In the exemplary embodiment, acooling plate 130 is coupled in contact with at least a portion of eachcontrol subsystem 110 to facilitate cooling each control subsystem 110.Moreover, in other embodiments, in addition to, or alternatively to,cooling plate 130, one or more control subsystems 110 may be cooledusing other structures and/or means.

The cooling fluid may facilitate cooling each cooling plate 130 usingany suitable process, structure, and/or means. For example, as shown inFIG. 3, in the exemplary embodiment, each cooling plate 130 is formedwith, or includes, a channel 150. In the exemplary embodiment, channel150 is coupled to, and/or is adjacent to, one side of cooling plate 130or may extend along both sides of cooling plate 130. Additionally, oralternatively, channel 150 may be an internal passageway that extendsthrough cooling plate 130. Each channel 150 is coupled in flowcommunication with a respective inlet portion 129, 132, 134, 136, and138 and a respective outlet portion 140, 142, 144, 146, and 148 of eachrespective subsystem 120, 122, 124, 126, and 128. When channel 150 ispositioned within or, adjacent to, cooling plate 130, heat is conductedfrom each respective subsystem 120, 122, 124, 126, and 128 to coolingplate 130 and then is convected out by the flowing fuel.

As shown in FIG. 3, cooling plate 130 includes fittings positionedbetween inlet portion 117 and outlet portion 119. Fittings may be anysuitable seal positioned between inlet portion 117 and outlet portion119 to cooling plate 130. More specifically, in the exemplaryembodiment, cooling fluid flows into cooling plate 130 through inletportion 134 and exits cooling plate 130 through outlet portion 144.

In the exemplary embodiment, control subsystem 110 includes adifferential pressure sensor (DPS) 152. For example, in the exemplaryembodiment, DPS 152 is a differential pressure switch. In addition to,or alternatively to, DPS 152 may be any suitable device and/or meansused to sense a difference in pressure. DPS 152 is positionable anywherewithin cooling system 100, cooling plate 130, or within controlsubsystem 110. DPS 152 measures a pressure difference between portionsof cooling system 100. In one embodiment, the difference in pressure incooling system 100 is measured by calculating a difference in pressurebetween an inlet and an outlet of cooling system 100. In a particularembodiment, DPS 152 may be fluidly coupled to inlet portion 117 andoutlet portion 119 for sensing a difference in pressure of cooling fluidwithin inlet and outlet portions 117 and 119.

In the exemplary embodiment, DPS 152 is positioned in flow communicationbetween inlet portion 134 and outlet portion 144. As such, DPS 152senses a difference in pressure between cooling fluid flowing throughinlet portion 134 and cooling fluid flowing through outlet portion 144.A sensed difference in pressure indicates cooling fluid is flowingthrough cooling system 100. Moreover, in the exemplary embodiment,because control subsystems 110 are positioned in a parallel flowrelationship relative to cooling system 100, if DPS 152 senses adifference in pressure between cooling fluid inlet portion 134 andoutlet portion 144, such a difference indicates that cooling fluid isalso flowing to, and/or adjacent to, those specific control subsystems110.

FIG. 4 is a flowchart illustrating exemplary logic used when testingcooling system 100 utilizing DPS 152 (shown in FIG. 3). Duringoperation, cooling system 100 provides cooling flow to each controlsubsystem 110 of engine 10. Specifically, in the exemplary embodiment,fuel flows from the fuel tank at tank boost pressure through conduitsystem 114 to each of control subsystems 110.

In one embodiment, DPS 152 and sensor 112 cooperate to verify thedifference in pressure and the pressure signals from the fuel sourcesupplied to cooling system 100 are present confirming that cooling fuelis capable of flowing through cooling system 100. DPS 152 iselectrically coupled to a processor-based application (not shown).Sensor 112 is also electrically coupled to the processor-basedapplication. The term processor, as used herein, refers tomicroprocessors, application specific integrated circuits (ASIC), logiccircuits, and any other circuit or processor capable of testing coolingsystem 100 as described herein. For example, in the exemplaryembodiment, DPS 152 is electrically coupled to the processor-basedapplication located within a control subsystem 110. More specifically,in the exemplary embodiment, the processor-based application is locatedwithin PHAM 120. Alternatively, the processor-based application may belocated within a portion of control system 99. DPS 152 and sensor 112verify the difference in pressure and the pressure signals from the fuelsource supplied to cooling system 100 are present. 112

The processor-based application receives an indication 158 from DPS 152of whether a difference in pressure exists between inlet portion 117 andoutlet portion 119. A difference in pressure sensed between coolingfluid within inlet portion 117 and outlet portion 119 is indicative ofwhether cooling fluid is flowing through cooling system 100. Forexample, in the exemplary embodiment, DPS 152 is in a closed positionprior to sensing a difference in pressure between inlet portion 117 andoutlet portion 119. Alternatively, DPS 152 may be in an open positionwhen there is a difference in pressure between inlet portion 117 andoutlet portion 119. In the exemplary embodiment, the processor-basedapplication also receives an indication 159 from sensor 112 that thereis pressurized fluid within cooling system 100 such that pressurizedfluid is supplied from the fuel source to cooling system 100.

In the exemplary embodiment, if sensor 112 detects pressure and DPS 152is in a closed position signifying a difference in pressure betweeninlet portion 117 and outlet portion 119, then the processor-basedapplication will conclude that cooling fluid is flowing through coolingsystem at 161.

In the exemplary embodiment, if sensor 112 detects pressure and DPS 152is in an open position signifying there is no difference in pressurebetween inlet portion 117 and outlet portion 119, then theprocessor-based application will conclude that cooling fluid is notflowing through cooling system at 162. If cooling fluid is not flowingthrough cooling system 100, processor-based application will output awarning. For example, in the exemplary embodiment, the warning is analarm.

In the exemplary embodiment, if sensor 112 does not detect cooling fluidis flowing from the source of cooling fluid and DPS 152 is in a closedposition, then the processor-based application will conclude that theswitch is faulted 164.

In the exemplary embodiment, if sensor 112 does not detect cooling fluidis flowing from the source of cooling fluid and DPS 152 is in an openposition, then the processor-based application will conclude that thesystem is not in operation 166. The method herein tests cooling system100 for use in a gas turbine engine 10 control system 110. The methodincludes connecting an inlet 117 of cooling system 100 to a DPS 152. Themethod further includes connecting an outlet 119 of cooling system 100to the DPS 152, and determining whether or not a difference in pressureexists between the inlet and outlet 117 and 119 wherein such a pressuredifference is indicative of whether cooling fluid is flowing through thecooling system 100.

The above-described cooling system facilitates preventing electronicfailure in an engine for lack of coolant flow. More specifically, thecooling system can be tested to see if fuel is flowing therethrough. Thetest is utilized after engine installation or after a maintenance actionon the engine. The test can also be conducted after starting the engineand either prior to takeoff of the plane. Additionally, the test can beconducted while the plane is in the air.

Exemplary embodiments of cooling systems are described above in detail.Each cooling system is not limited to use with the specific embodimentsdescribed herein, but rather, each cooling system can be utilizedindependently and separately from other components described herein.Moreover, the invention is not limited to the embodiments of thedifferential pressure switches described above in detail. Rather, othervariations of differential pressure transducers or sensors may beutilized within the spirit and scope of the claims.

While the invention has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

1. A method for testing a cooling system for use in a gas turbine enginecontrol system, said method comprising: connecting an inlet of thecooling system to a differential pressure sensor; connecting an outletof the cooling system to the differential pressure sensor; determiningwhether the cooling fluid is pressurized using a first pressure sensoroperatively coupled to the gas turbine engine control system; anddetermining whether or not a difference in pressure exists between theinlet and outlet, wherein such a pressure difference is indicative ofwhether cooling fluid is flowing through the cooling system.
 2. A methodin accordance with claim 1 wherein the differential pressure sensor is adifferential pressure switch, said method further comprises receiving anindication from the differential pressure switch comprises receiving anindication of whether the differential pressure switch is in one of anopen position and a closed position.
 3. A method in accordance withclaim 1 further comprising receiving an indication from a pressuresensor that cooling fluid pressure is supplied to the cooling system. 4.A method in accordance with claim 1 further comprising: generating awarning that cooling fluid is not flowing through the cooling systembased, at least in part, on an indication received from the differentialpressure sensor that there is not the difference in pressure betweencooling fluid within the inlet and outlet.
 5. A method in accordancewith claim 4 wherein generating a warning that cooling fluid is notflowing through the cooling system further comprises generating awarning that is also based, at least in part, on an indication from apressure sensor that there is cooling fluid pressure supplied to thecooling system.
 6. A method in accordance with claim 1 furthercomprising generating an indication that the differential pressureswitch has failed based, at least in part, on an indication receivedfrom the differential pressure switch that a pressure difference existspressure between cooling fluid within the inlet and outlet and anindication from a pressure sensor that there is no cooling fluidpressure supplied to the cooling system.
 7. A method in accordance withclaim 1 further comprising generating a signal that at least one of theinlet and the outlet is disconnected based at least in part on anindication received from the differential pressure sensor that there isnot the difference in pressure between cooling fluid within the inletand outlet. 8.-19. (canceled)
 20. A method for testing a cooling systemfor use in a gas turbine engine control system, said method comprising:coupling a differential pressure sensor between an inlet and an outletof the cooling system, the differential pressure sensor configured tosense a pressure difference between the inlet and the outlet of thecooling system; coupling a first pressure sensor to the gas turbineengine control system, the first pressure sensor configured to determinewhether the cooling fluid is pressurized; determining whether or not adifference in pressure exists between the inlet and outlet, wherein sucha pressure difference is indicative of whether cooling fluid is flowingthrough the cooling system; and determining a fault in the differentialpressure sensor when said differential pressure sensor indicates apressure difference and the first pressure sensor determines that thecooling fluid is not pressurized.